Complex telecommunications systems are often of a modular design. Such systems may have an enclosure housing a base or fixed circuit board into which a number of differently configured or variant circuit cards may be inserted in a pluggable manner. The fixed circuit board typically has one or more multi-contact receptacle connectors into each of which a multi-contact plug connector on a variant circuit card may be inserted.
In some systems, the base or fixed circuit board may be provided with rear wiring which connects all the mating plug-in cards, and may be configured as a cable harness, as a winding bridge, or as a backplane. To allow a free choice of position or slot for any desired card, contacts of the same type on the base circuit board may be connected to one another to form a parallel bus. In such systems, the configuration of contacts on each card is identical and matches that of the base circuit board.
For example, U.S. Pat. No. 5,547,386 to Fredberg provides an apparatus adapted for coaction with a number of circuit boards. The apparatus has a backplane adapted for coaction with a number of circuit boards arranged in side-by-side relationship and including a number of mutually adjacent and mutually spaced elongated, narrow backplane-related connector fields, each of which is adapted for firm but easily removed mechanical and electrical coaction with a corresponding connector field related to an edge-part of respective circuit boards. A number of first selected backplane-related connector fields are connected electrically to a first bus, and a number of second selected backplane related connector fields are connected electrically to a second bus. The backplane-related connector fields are divided into a predetermined number of groups wherein each group is allotted a part-section of the backplane and wherein the first connector fields of respective groups are joined together and connect to the first bus. Each backplane-related group is allocated the same number of connector fields and each second connector field of each group are mutually joined and connect to the second bus. Also see U.S. Pat. Nos. 5,896,473 and 6,855,001 to Kaspari and Goers et al., respectively.
One problem with such systems is that they restrict the flexibility of card design. In particular, cards having different contact requirements must still mate with the standard contact arrangement on the base or fixed circuit board. This is wasteful as it causes an increase in the number of necessary contacts on each card and the complexity of the backplane wiring. In addition, the overall size of the connector on each card increases with the number of contacts required.
A need therefore exists for an improved connector system for mating variant circuit cards to a fixed circuit board. Accordingly, a solution that addresses, at least in part, the above and other shortcomings is desired.